Data Base Management System
A Database Management System (DBMS) is a program that controls creation, maintenance and use of a database. DBMS can be termed as File Manager that manages data in a database rather than saving it in file systems.
1)DBMS Contains set of standards or rules and they are converted into concepts or features.
2)DBMS used to store ,manage(insert,update,delete),access the data.
3)In DBMS data will be stored in the form of Tables.Every Table will contain two dimenstions(Rows & Columns).
DBMS Features
1) Redenduncy
-> Duplicate values(data) can be reduced.
-> Inconsistency means incorrect data can be reduced (or)the data which is not meaningful.
-> if table contains redudency then inconsistancy may exist in the table.by using constraints redudency and inconsistancy can be reduced.
2) Security
-> By using authentication and authorization can provide the security.
-> Authentication means Identification of users.It is used to check whether the given username is registered or not.
-> Authorization is used to check whether the user has permissions or rights to work with database and tables.
3) Data Integrity
-> if the table maintain standards or data intergrity then valid or meaningful data can be stored in tables.This will done by using constraints.
4) Atomcity
-> Atomcity taken from greekword called atom.Atom means individual.Atomcity means all the commands in the transaction will execute ot none of them will execute.
-> Transcation means set of sql commands will execute as a unit.
-> Transcation will work with ACID properties
a) A- Atomicity
b) C- Consistancy
c) I- Isolation
d) D- Durability